Bug 109252 - external monitor flicker with error [drm:intel_dp_get_link_train_fallback_values [i915]] *ERROR* Link Training Unsuccessful
Summary: external monitor flicker with error [drm:intel_dp_get_link_train_fallback_val...
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
Depends on:
Reported: 2019-01-09 05:39 UTC by alex.tu
Modified: 2019-09-03 12:43 UTC (History)
4 users (show)

See Also:
i915 platform:
i915 features:

the dmesg got after issue happened. (152.03 KB, text/plain)
2019-01-09 05:39 UTC, alex.tu
no flags Details
dmesg from drm-tip 2019-01-18 (10.75 MB, text/plain)
2019-01-18 09:25 UTC, Kai-Heng Feng
no flags Details

Description alex.tu 2019-01-09 05:39:20 UTC
Created attachment 143026 [details]
the dmesg got after issue happened.

VGA of Host Machine: 
00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:3e9b] (prog-if 00 [VGA controller])

Monitor:  Dell P2317H (can also reproduce it on other monitor)

steps to reproduce:
1. connect external monitor 
2. see screen on external monitor
3. get flicker on external monitor
4. switch display mode by "windows+p" still get flicker or even dark screen.
5. see error message on dmesg
[drm:intel_dp_get_link_train_fallback_values [i915]] *ERROR* Link Training Unsuccessful
Comment 1 alex.tu 2019-01-09 10:24:43 UTC
this issue could be also reproduced by main line kernel 5.0.0-rc1
Comment 2 Radosław Szwichtenberg 2019-01-11 10:02:45 UTC
Please try to reproduce the error using drm-tip (https://cgit.freedesktop.org/drm-tip) and kernel parameters drm.debug=0x1e log_buf_len=4M, and if the problem persists attach the full dmesg from boot.
Comment 3 Kai-Heng Feng 2019-01-18 09:25:24 UTC
Created attachment 143148 [details]
dmesg from drm-tip 2019-01-18

No more "[drm:intel_dp_get_link_train_fallback_values [i915]] *ERROR* Link Training Unsuccessful" but I still observe the issue.
Comment 4 Lakshmi 2019-07-03 09:20:51 UTC
Alex, Do you still see the issue? Can you please attach the latest dmesg from latest kernel (preferably with drmtip)?

My apologies for not responding on this issue.
Comment 5 Lakshmi 2019-09-03 12:01:08 UTC
Alex, any updates here?
Comment 6 alex.tu 2019-09-03 12:43:32 UTC
Sorry for response late. This issue not happened to another machine which is same configuration as the problematic one. So, we treated it as hardware issue.

Thanks for your following.

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